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Search Results: 1 - 10 of 104327 matches for " Limei Zhang "
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An Action Research on Deep Word Processing Strategy Instruction
Limei Zhang
English Language Teaching , 2010, DOI: 10.5539/elt.v3n1p103
Abstract: For too long a time, how to memorize more words and keep them longer in mind has been a primary and everlasting problem for vocabulary teaching and learning. This study focused on deep processing as a word memorizing strategy in contextualizing, de- and re- contextualizing learning stages. It also examined possible effects of such pedagogy on vocabulary competence and attitude towards word learning. The context of the action research was an 11-week deep word processing strategy instruction program, involving 39 non-English major freshmen. The results showed that teacher’s strategy-based instructional intervention affected the changes both in learners’ vocabulary competence and in teachers’ and learners’ attitude toward word learning. These findings were discussed in terms of some issues deserving more considerations. And accommodations for future study were also made.
Development of High Efficient and Low Toxic Oil Spill Dispersants based on Sorbitol Derivants Nonionic Surfactants and Glycolipid Biosurfactants  [PDF]
Dandan Song, Shengkang Liang, Qianqian Zhang, Jiangtao Wang, Limei Yan
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.41B004
Abstract: Dispersants, usually blending with several surfactants and a solvent, are used to enhance oil spill dispersion as small droplets in water column. Although there is growing acceptance of dispersants as a counter measure to marine oil spills around the world, the two major issues with the dispersants are their toxicity to marine life and dispersion effectiveness (DE) for crude-oil, especially for heavy oil. To develop more efficient and less toxic dispersants, two kinds of sorbitol derivant nonionic surfactant (polysorbate 85 and sorbeth-40 tetraoleate), two kinds of glycolipid biosurfactants (rhamnolipid and sophorolipid) and less toxic solvent ethylene glycol butyl ether were chosen in this study, and two dispersant formulations were optimized by uniform design methods. Effects of dispersant-to-oil ratio, temperature, salinity and pH on the performance of the two optimized dispersants were investigated. The two dispersants had high dispersion effectiveness (DE) for heavy crude oil, while both dispersants keep high DE at the dispersant-to-oil ratio below 1:25 and the temperature above 5 ℃. In addition, the two dispersants also performed well in a wide range of salinity and pH values. Finally, toxicity tests revealed that the two dispersants showed low toxicity to two kinds of fish (Danio rerio and Microgobius gulosus).


The λ-Characteristics of the Ring Laser Based on Non-Uniform SOA  [PDF]
Zhi Wang, Limei Zhang, Yingfeng Liu, Lanlan Liu
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.17013
Abstract: Semiconductor optical amplifier-based ring cavity laser (SOA-RL), which has been widely used in optical communications, optical fiber sensing, and biophotonics fields, can be tuned at an ultra high speed up to Mega Hertz over 100 nm bandwidth range with high SNR and flatness output. A steady-state model and segmentation algorithms are employed to investigate the gain spectra of four kinds of non-uniform SOA and the lasing wavelength of the SOA-RL. It shows that the dependence of the lasing wavelength on the average width is stronger when the light propagates from narrower to wider end than conversely, and there are some particular structures to show ultra high stability lasing wavelength. It is supposed that the main reason could be the carrier density distribution along the propagation.
Relationship between Cr-Al Interaction and the Performance of Cr-Al2O3 Catalysts for Isobutane Dehydrogenation  [PDF]
Deren Fang, Jinbo Zhao, Shang Liu, Limei Zhang, Wanzhong Ren, Huimin Zhang
Modern Research in Catalysis (MRC) , 2015, DOI: 10.4236/mrc.2015.42007
Abstract: A series of catalysts were prepared using the kneading molding method and the impregnation method as well as the dry mix method by using different raw materials. By using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR) techniques, we studied the relationship between the catalyst performance and the Cr-Al interaction in the catalytic dehydrogenation of isobutane. The results demonstrated that the Cr-Al interaction in the catalyst had a direct influence on the catalytic activity and the selectivity of isobutene. The catalysts prepared using the kneading molding method had higher catalytic activity and isobutene selectivity than those prepared using the dry mix method. By comparison, XRD, XPS, and TPR results showed that the greater the Cr-Al interaction in the catalyst was, the higher the catalytic activity was. Here, we propose a mechanism of isobutane dehydrogenation.
Description of the FDML Laser with Quasi-steady State Model of the SOA  [PDF]
Zhi Wang, Limei Zhang, Lanlan Liu, Zhenchao Sun, Yingfeng Liu, Fu Wang
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B015

Experiments and simulations demonstrate that an SOA-based ring cavity can operate as a tunable laser, wavelength- swept laser or Fourier-domain-mode-locking laser according to the relation between the roundtrip frequency and the sweeping frequency of the filter.

Birefringence of Muscovite Mica Plate Temperature Effect in the Ultraviolet and Visible Spectrum
Xu Zhang,Fuquan Wu,Limei Qi,Xia Zhang,Dianzhong Hao
Physics , 2014,
Abstract: We developed a method to measure the phase retardation and birefringence of muscovite mica plate in the temperature range of 223K to 358K within the spectrum of 300 to 700 nm. The phase retardation data is gained through the standard transmission ellipsometry using spectroscopic ellipsometer. With the phase retardation and thickness of the mica plate we can calculate its birefringence dispersion. Our results give abundant phase retardation and birefringence data of muscovite mica in the ultraviolet and visible spectrum from 223K to 358K. From the experimental data, the phase retardation and birefringence will drop down at the fixed wavelength when the temperature rises. The accuracy of the birefringence of mica plate is better than 3.5e-5.
Phase Retardation and Birefringence of the Crystalline Quartz Plate in the Ultraviolet and Visible Spectrum
Xu Zhang,Fuquan Wu,Limei Qi,Xia Zhang,Dianzhong Hao
Physics , 2014,
Abstract: A method for measuring the phase retardation and birefringence of crystalline quartz wave plate in the ultraviolet and visible spectrum is demonstrated using spectroscopic ellipsometer. After the calibration of the crystalline quartz plate, the experimental data are collected by the photodetector and sent to the computer. According to the outputted data, the retardation can be obtained in the range of 190 to 770 nm. With the retardation data, the birefringence for the quartz can be calculated in the same spectrum with an accuracy of better than . The birefringence results enrich the crystalline quartz birefringence data especially in the ultraviolet spectrum.
Meromorphic Functions Sharing Three Values  [PDF]
Changjun Li, Limei Wang
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.26095
Abstract: In this paper, we prove a result on the uniqueness of meromorphic functions sharing three values counting multiplicity and improve a result obtained by Xiaomin Li and Hongxun Yi.
Comparative Studies of the Pyrolytic and Kinetic Characteristics of Maize Straw and the Seaweed Ulva pertusa
Naihao Ye,Demao Li,Limei Chen,Xiaowen Zhang,Dong Xu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012641
Abstract: Seaweed has attracted considerable attention as a potential biofuel feedstock. The pyrolytic and kinetic characteristics of maize straw and the seaweed Ulva pertusa were studied and compared using heating rates of 10, 30 and 50°C min?1 under an inert atmosphere. The activation energy, and pre-exponential factors were calculated by the Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Popescu methods. The kinetic mechanism was deduced by the Popescu method. The results indicate that there are three stages to the pyrolysis; dehydration, primary devolatilization and residual decomposition. There were significant differences in average activation energy, thermal stability, final residuals and reaction rates between the two materials. The primary devolatilization stage of U. pertusa can be described by the Avramic-Erofeev equation (n = 3), whereas that of maize straw can be described by the Mampel Power Law (n = 2). The average activation energy of maize straw and U. pertusa were 153.0 and 148.7 KJ mol?1, respectively. The pyrolysis process of U.pertusa would be easier than maize straw. And co-firing of the two biomass may be require less external heat input and improve process stability. There were minor kinetic compensation effects between the pre-exponential factors and the activation energy.
The subcellular localization of IGFBP5 affects its cell growth and migration functions in breast cancer
Mustafa Akkiprik, Limei Hu, Aysegul Sahin, Xishan Hao, Wei Zhang
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-103
Abstract: To test this hypothesis, we generated wild-type and mutant IGFBP5 expression constructs. The mutation occurs within the nuclear localization sequence (NLS) of the protein and is generated by site-directed mutagenesis using the wild-type IGFBP5 expression construct as a template. Next, we transfected each expression construct into MDA-MB-435 breast cancer cells to establish stable clones overexpressing either wild-type or mutant IGFBP5.Functional analysis revealed that cells overexpressing wild-type IGFBP5 had significantly lower cell growth rate and motility than the vector-transfected cells, whereas cells overexpressing mutant IGFBP5 demonstrated a significantly higher ability to proliferate and migrate. To illustrate the subcellular localization of the proteins, we generated wild-type and mutant IGFBP5-pDsRed fluorescence fusion constructs. Fluorescence microscopy imaging revealed that mutation of the NLS in IGFBP5 switched the accumulation of IGFBP5 from the nucleus to the cytoplasm of the protein.Together, these findings imply that the mutant form of IGFBP5 increases proliferation and motility of breast cancer cells and that mutation of the NLS in IGFBP5 results in localization of IGFBP5 in the cytoplasm, suggesting that subcellular localization of IGFBP5 affects its cell growth and migration functions in the breast cancer cells.Insulin-like growth factor (IGF) binding protein-5 (IGFBP5) is the most evolutionarily conserved member in a family of 6 high-affinity IGF-binding proteins [1,2]. IGFBP5 has been shown to have a potential role in carcinogenesis that involves 2 main pathways [3,4]. One is the IGF-dependent pathway. The other is the IGF-independent pathway, which is more complicated and less understood than the IGF-dependent pathway. Recently, Duan and colleagues showed that IGFBP5 promotes cell differentiation by regulating IGF-II actions [5]. Many of the recently published studies of IGFBP5 have focused on the involvement of the protein in apoptosis, pro
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